The present invention relates to an apparatus for attaching an accessory, such as a rail, to the side wall of a pick-up truck cargo box. In particular, the invention relates to an improved arrangement for attaching a clamp to a rail for the purpose of mounting the rail to a pick-up box side wall.
A tonneau cover is mounted over the cargo box of pick-up trucks to protect the cargo box and its contents. Tonneau covers are typically mounted to the cargo box by first mounting rails to the top of the cargo box. The rails include features for attaching the tonneau cover to the rails in such a manner that the rails are substantially covered by the tonneau cover, leaving the truck and tonneau cover with a neat appearance.
In a typical tonneau cover arrangement, the rails are attached to one another, forming a rectangular frame overlying the top of the cargo box side walls, tailgate and front wall. The two rails upon the side walls are attached to the cargo box side walls to mount the entire frame to the cargo box. The preferred manner of attaching the rails to the cargo box side walls is with clamps. This avoids the necessity of drilling any holes in the cargo box sheet metal. Holes drilled in the sheet metal provide an opportunity for rust to form and also permanently mar the appearance of the pick-up truck.
Depending upon the length of a cargo box, three to five clamps are used to mount the rails to each side wall. One clamp arrangement for attaching a tonneau cover rail is shown in U.S. Pat. No. 5,121,960, issued to Applicant of the present invention and hereby incorporated by reference. The rail, as shown in FIG. 11 of the '960 patent, has a lower base wall, an upper top wall and a vertical web which extends between the base wall and the top wall, approximately midway between the inboard and outboard edges of the rail. Along the inboard edge of the rail, the top wall, base wall and web form a generally C-shaped clamp slot. This slot receives the head of one of two clamp members that form each clamp. The clamp member has three lips which are seated into the C-shaped slot of the rail to apply the desired forces to the rail when the clamp member is clamped to the cargo box side wall.
While the clamp arrangement shown in the '960 patent properly performs in clamping the rail to the cargo box, assembly of the clamp to the rail can be difficult. Because of the nature in which the clamp member is inserted into the rail slot, the rail and clamp member must be rotated relative to one another to insert the clamp member into the rail slot. If the clamp members are attached to the rails before the frame is placed on the cargo box, it is necessary to hold each of the clamp members in a vertical position while lowering the frame onto the cargo box to avoid scratching of the pick-up truck. This requires many hands, making it difficult to install the tonneau cover. As an alternative, the rectangular frame can be placed on the cargo box and then each side rail lifted to provide the necessary clearance to rotate the clamp members onto the frame side rails. Again, several hands are required to hold the clamp members vertical while the rail is lowered onto the cargo box. A third option is to separately place the frame rails onto the cargo box, clamp the side rails onto the side walls and then attach the front and rear frame rails to the side rails. This is also difficult to do with the side rails already attached to the cargo box.
Another tonneau cover configuration provides a clamp member with an enlarged head which completely fills the slot in the rail. This is shown in U.S. Pat. No. 5,275,458, also incorporated by reference. While this configuration avoids the rotation of the clamp members when they hang from the rail, it requires the clamp members to be slid onto the rails from the rail ends prior to assembly of the rectangular frame. Depending upon the manufacturing tolerances, sliding of the clamp members through the rail slot can be difficult.
Accordingly, it is the object of the present invention to provide an improved clamp and rail structure which enables the clamp or attaching members to be attached to the rail and remain generally in their installed vertical orientation so that the rectangular frame can be placed on the cargo box and the attaching members later mounted to the rail without lifting the rail to provide needed clearance. It is a further object to provide a clamp and rail structure that enables the clamp members to be placed anywhere on the rail without first sliding the clamp members from one end of the rail.
The present invention achieves the above objective by providing the rail with one or more upwardly open channels. The clamp or attaching member mounted on the rail is provided with one or more downwardly open hooks which are placed into the channels of the rail. The attaching member hooks are sized to fit relatively snugly within the rail channels to prevent rotation of the attaching member relative to the rail. Thus, the attaching members are held in their normal installed vertical orientation relative to the rail. There is no need to hold the attaching members in place while lowering the rail onto the box. Furthermore, the attaching members can be easily "hung" onto the rail wherever desired without sliding the attaching members in a rail slot from one end of the rail.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.